Effects of capsaicin on tension in the slow skeletal muscle fibers of the chicken (LB823)

Abstract

Skeletal muscle possesses two types of muscle fibers: 1) fast and 2) slow or tonic. In skeletal muscle fibers exists evidence of vanilloid receptors presence. It is known that vanilloid receptor TRPV1 is activated by capsaicin. On the other hand, primary sensitive neurons from chicks the vanilloid receptors are capsaicin‐insensitive.By using isometric recording in bundles of the slow skeletal muscle fibers of one or two‐week age chicken dissected from the anterior latissimus dorsi muscle, the effect of capsaicin (10 μM) on caffeine (6 mM) evoked contractures was measured in the presence and absence of the antagonist capsazepine (1 μM). Capsaicin diminished maximum tension in the slow skeletal muscle fibers until 83.25±11.5%, (n=7, p=0.002) respecting to control, an effect that was partially reverted in the presence of the TRPV1 antagonist capsazepine. However, this reduction of maximum tension was not statistically significative (mean was 91.30±5.04%, n=5, p>0.05). These results suggest capsaicin is capable to activate the vanilloid receptor in avian skeletal muscle fibers.Grant Funding Source: CIC2014‐RMP